The present invention relates to a battery pack tray constituting a battery pack for mounting a battery on a vehicle such as an electric vehicle or a hybrid vehicle.
In an electric vehicle which uses an electric motor as a driving source, or a hybrid vehicle which uses an electric motor and an engine as driving sources, a battery pack which houses batteries for supplying electric power to the motor is mounted.
In such a battery pack, a plurality of battery modules are housed in a battery housing member such as a battery pack tray.
JP-A-2010-284984 discloses a related art of a battery housing member such as a battery pack tray.
According to JP-A-2010-284984, a battery pan includes: a bottom surface potion on which batteries are to be placed; a wall portion which is upward bent from an outer peripheral edge portion of the bottom surface potion; a plurality of cross members which are coupled to the upper surface of the bottom surface potion, and in which the both ends are coupled to the wall portion; an outer peripheral frame which is continuous on the entire outer periphery of the wall portion; and a flange which is outward bent from the upper surface of the wall portion.
In the outer peripheral frame in the front of the battery pan, furthermore, a front stay which is to be coupled to a vehicle cross member is disposed in the entire intermediate portion of the battery pan in the vehicle width direction.
In the outer peripheral frame in each of the both sides of the battery pan, a side stay which is to be coupled to a vehicle side frame is disposed in the entire region from a front end portion to an intermediate portion in the vehicle anteroposterior direction.
The front and side stays are formed by bending a flat plate.
According to JP-A-2010-284984, however, the outer peripheral frame is attached to the entire outer periphery of the wall portion of the battery pan. The outer peripheral frame has a structure in which the outer peripheral frame outward projects from the outer periphery of the wall surface so as to maintain the strength and rigidity of the battery pan, and prevent rainwater churned by vehicle wheels from being directly sprayed to a joint portion between the battery pan and a cover attached to the upper surface of the battery pan.
Therefore, the shape of the outer peripheral frame has the strength and rigidity which are greater than those that are originally required in an outer peripheral frame. Consequently, the outer peripheral frame is heavy, and problematic in terms of material cost and handling.
In each of the front and side stays, moreover, one end is fixed to the outer peripheral frame, and the other end is fastened to the corresponding one of the vehicle cross and side members.
However, the dimension of the side frames in the vehicle width direction depends on the size and shape of the vehicle. As described above, the outer peripheral edge of the outer peripheral frame outward projects from the wall surface of the battery pan in a degree greater than required. Therefore, the relative distances between the outer peripheral edge of the outer peripheral frame, and the cross and side frames which are the attaching portions on the side of the vehicle body are short. As a result, there is a further problem in that a space in which a shape countermeasure for the strength and rigidity of the front and side stays is hardly ensured.